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7941b27b PA |
1 | /* |
2 | * Functions for dealing with DT resolution | |
3 | * | |
4 | * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com> | |
5 | * Copyright (C) 2012 Texas Instruments Inc. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * version 2 as published by the Free Software Foundation. | |
10 | */ | |
11 | ||
606ad42a RH |
12 | #define pr_fmt(fmt) "OF: resolver: " fmt |
13 | ||
7941b27b PA |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/of.h> | |
17 | #include <linux/of_device.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/ctype.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/string.h> | |
22 | #include <linux/slab.h> | |
23 | ||
24 | /* illegal phandle value (set when unresolved) */ | |
25 | #define OF_PHANDLE_ILLEGAL 0xdeadbeef | |
26 | ||
27 | /** | |
28 | * Find a node with the give full name by recursively following any of | |
29 | * the child node links. | |
30 | */ | |
fad556bf | 31 | static struct device_node *find_node_by_full_name(struct device_node *node, |
7941b27b PA |
32 | const char *full_name) |
33 | { | |
34 | struct device_node *child, *found; | |
35 | ||
9f27ede4 | 36 | if (!node) |
7941b27b PA |
37 | return NULL; |
38 | ||
9f27ede4 | 39 | if (!of_node_cmp(node->full_name, full_name)) |
82f68756 | 40 | return of_node_get(node); |
7941b27b PA |
41 | |
42 | for_each_child_of_node(node, child) { | |
fad556bf | 43 | found = find_node_by_full_name(child, full_name); |
82f68756 AKC |
44 | if (found != NULL) { |
45 | of_node_put(child); | |
7941b27b | 46 | return found; |
82f68756 | 47 | } |
7941b27b PA |
48 | } |
49 | ||
50 | return NULL; | |
51 | } | |
52 | ||
f94823f2 | 53 | static phandle live_tree_max_phandle(void) |
7941b27b PA |
54 | { |
55 | struct device_node *node; | |
56 | phandle phandle; | |
57 | unsigned long flags; | |
58 | ||
7941b27b PA |
59 | raw_spin_lock_irqsave(&devtree_lock, flags); |
60 | phandle = 0; | |
61 | for_each_of_allnodes(node) { | |
62 | if (node->phandle != OF_PHANDLE_ILLEGAL && | |
63 | node->phandle > phandle) | |
64 | phandle = node->phandle; | |
65 | } | |
66 | raw_spin_unlock_irqrestore(&devtree_lock, flags); | |
67 | ||
68 | return phandle; | |
69 | } | |
70 | ||
25e16877 | 71 | static void adjust_overlay_phandles(struct device_node *overlay, |
7941b27b PA |
72 | int phandle_delta) |
73 | { | |
74 | struct device_node *child; | |
75 | struct property *prop; | |
76 | phandle phandle; | |
77 | ||
269f1a67 | 78 | /* adjust node's phandle in node */ |
25e16877 FR |
79 | if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL) |
80 | overlay->phandle += phandle_delta; | |
7941b27b | 81 | |
269f1a67 | 82 | /* copy adjusted phandle into *phandle properties */ |
25e16877 | 83 | for_each_property_of_node(overlay, prop) { |
7941b27b | 84 | |
9f27ede4 FR |
85 | if (of_prop_cmp(prop->name, "phandle") && |
86 | of_prop_cmp(prop->name, "linux,phandle")) | |
7941b27b PA |
87 | continue; |
88 | ||
7941b27b PA |
89 | if (prop->length < 4) |
90 | continue; | |
91 | ||
7941b27b | 92 | phandle = be32_to_cpup(prop->value); |
a67976ec | 93 | if (phandle == OF_PHANDLE_ILLEGAL) |
7941b27b PA |
94 | continue; |
95 | ||
25e16877 | 96 | *(uint32_t *)prop->value = cpu_to_be32(overlay->phandle); |
7941b27b PA |
97 | } |
98 | ||
25e16877 | 99 | for_each_child_of_node(overlay, child) |
f94823f2 | 100 | adjust_overlay_phandles(child, phandle_delta); |
7941b27b PA |
101 | } |
102 | ||
25e16877 FR |
103 | static int update_usages_of_a_phandle_reference(struct device_node *overlay, |
104 | struct property *prop_fixup, phandle phandle) | |
7941b27b | 105 | { |
7941b27b | 106 | struct device_node *refnode; |
25e16877 FR |
107 | struct property *prop; |
108 | char *value, *cur, *end, *node_path, *prop_name, *s; | |
109 | int offset, len; | |
7941b27b PA |
110 | int err = 0; |
111 | ||
25e16877 FR |
112 | value = kmalloc(prop_fixup->length, GFP_KERNEL); |
113 | if (!value) | |
7941b27b | 114 | return -ENOMEM; |
25e16877 | 115 | memcpy(value, prop_fixup->value, prop_fixup->length); |
7941b27b | 116 | |
269f1a67 | 117 | /* prop_fixup contains a list of tuples of path:property_name:offset */ |
25e16877 FR |
118 | end = value + prop_fixup->length; |
119 | for (cur = value; cur < end; cur += len + 1) { | |
120 | len = strlen(cur); | |
7941b27b | 121 | |
25e16877 FR |
122 | node_path = cur; |
123 | s = strchr(cur, ':'); | |
7941b27b | 124 | if (!s) { |
7941b27b PA |
125 | err = -EINVAL; |
126 | goto err_fail; | |
127 | } | |
128 | *s++ = '\0'; | |
129 | ||
25e16877 | 130 | prop_name = s; |
7941b27b PA |
131 | s = strchr(s, ':'); |
132 | if (!s) { | |
7941b27b PA |
133 | err = -EINVAL; |
134 | goto err_fail; | |
135 | } | |
7941b27b | 136 | *s++ = '\0'; |
624ab2a4 | 137 | |
7941b27b | 138 | err = kstrtoint(s, 10, &offset); |
9f27ede4 | 139 | if (err) |
7941b27b | 140 | goto err_fail; |
7941b27b | 141 | |
25e16877 | 142 | refnode = find_node_by_full_name(overlay, node_path); |
96d1c8e8 | 143 | if (!refnode) |
7941b27b | 144 | continue; |
7941b27b | 145 | |
25e16877 FR |
146 | for_each_property_of_node(refnode, prop) { |
147 | if (!of_prop_cmp(prop->name, prop_name)) | |
7941b27b PA |
148 | break; |
149 | } | |
82f68756 | 150 | of_node_put(refnode); |
7941b27b | 151 | |
25e16877 | 152 | if (!prop) { |
7941b27b PA |
153 | err = -ENOENT; |
154 | goto err_fail; | |
155 | } | |
156 | ||
25e16877 | 157 | *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle); |
7941b27b PA |
158 | } |
159 | ||
160 | err_fail: | |
25e16877 | 161 | kfree(value); |
7941b27b PA |
162 | return err; |
163 | } | |
164 | ||
da56d04c | 165 | /* compare nodes taking into account that 'name' strips out the @ part */ |
fad556bf | 166 | static int node_name_cmp(const struct device_node *dn1, |
da56d04c PA |
167 | const struct device_node *dn2) |
168 | { | |
169 | const char *n1 = strrchr(dn1->full_name, '/') ? : "/"; | |
170 | const char *n2 = strrchr(dn2->full_name, '/') ? : "/"; | |
171 | ||
172 | return of_node_cmp(n1, n2); | |
173 | } | |
174 | ||
7941b27b PA |
175 | /* |
176 | * Adjust the local phandle references by the given phandle delta. | |
269f1a67 FR |
177 | * |
178 | * Subtree @local_fixups, which is overlay node __local_fixups__, | |
179 | * mirrors the fragment node structure at the root of the overlay. | |
180 | * | |
181 | * For each property in the fragments that contains a phandle reference, | |
182 | * @local_fixups has a property of the same name that contains a list | |
183 | * of offsets of the phandle reference(s) within the respective property | |
184 | * value(s). The values at these offsets will be fixed up. | |
7941b27b | 185 | */ |
25e16877 FR |
186 | static int adjust_local_phandle_references(struct device_node *local_fixups, |
187 | struct device_node *overlay, int phandle_delta) | |
7941b27b | 188 | { |
25e16877 FR |
189 | struct device_node *child, *overlay_child; |
190 | struct property *prop_fix, *prop; | |
da56d04c PA |
191 | int err, i, count; |
192 | unsigned int off; | |
193 | phandle phandle; | |
7941b27b | 194 | |
25e16877 | 195 | if (!local_fixups) |
7941b27b PA |
196 | return 0; |
197 | ||
25e16877 | 198 | for_each_property_of_node(local_fixups, prop_fix) { |
da56d04c | 199 | |
7941b27b | 200 | /* skip properties added automatically */ |
25e16877 FR |
201 | if (!of_prop_cmp(prop_fix->name, "name") || |
202 | !of_prop_cmp(prop_fix->name, "phandle") || | |
203 | !of_prop_cmp(prop_fix->name, "linux,phandle")) | |
7941b27b PA |
204 | continue; |
205 | ||
25e16877 | 206 | if ((prop_fix->length % 4) != 0 || prop_fix->length == 0) |
da56d04c | 207 | return -EINVAL; |
25e16877 | 208 | count = prop_fix->length / sizeof(__be32); |
da56d04c | 209 | |
25e16877 FR |
210 | for_each_property_of_node(overlay, prop) { |
211 | if (!of_prop_cmp(prop->name, prop_fix->name)) | |
da56d04c PA |
212 | break; |
213 | } | |
214 | ||
25e16877 | 215 | if (!prop) |
da56d04c | 216 | return -EINVAL; |
da56d04c PA |
217 | |
218 | for (i = 0; i < count; i++) { | |
25e16877 | 219 | off = be32_to_cpu(((__be32 *)prop_fix->value)[i]); |
ea8229b7 | 220 | if ((off + 4) > prop->length) |
da56d04c | 221 | return -EINVAL; |
da56d04c | 222 | |
624ab2a4 FR |
223 | phandle = be32_to_cpu(*(__be32 *)(prop->value + off)); |
224 | phandle += phandle_delta; | |
225 | *(__be32 *)(prop->value + off) = cpu_to_be32(phandle); | |
da56d04c PA |
226 | } |
227 | } | |
228 | ||
269f1a67 FR |
229 | /* |
230 | * These nested loops recurse down two subtrees in parallel, where the | |
231 | * node names in the two subtrees match. | |
232 | * | |
233 | * The roots of the subtrees are the overlay's __local_fixups__ node | |
234 | * and the overlay's root node. | |
235 | */ | |
25e16877 | 236 | for_each_child_of_node(local_fixups, child) { |
da56d04c | 237 | |
25e16877 FR |
238 | for_each_child_of_node(overlay, overlay_child) |
239 | if (!node_name_cmp(child, overlay_child)) | |
da56d04c PA |
240 | break; |
241 | ||
25e16877 | 242 | if (!overlay_child) |
da56d04c | 243 | return -EINVAL; |
da56d04c | 244 | |
25e16877 | 245 | err = adjust_local_phandle_references(child, overlay_child, |
da56d04c | 246 | phandle_delta); |
9f27ede4 | 247 | if (err) |
7941b27b PA |
248 | return err; |
249 | } | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | /** | |
269f1a67 FR |
255 | * of_resolve_phandles - Relocate and resolve overlay against live tree |
256 | * | |
257 | * @overlay: Pointer to devicetree overlay to relocate and resolve | |
258 | * | |
259 | * Modify (relocate) values of local phandles in @overlay to a range that | |
260 | * does not conflict with the live expanded devicetree. Update references | |
261 | * to the local phandles in @overlay. Update (resolve) phandle references | |
262 | * in @overlay that refer to the live expanded devicetree. | |
263 | * | |
264 | * Phandle values in the live tree are in the range of | |
265 | * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay | |
266 | * also begin with at 1. Adjust the phandle values in the overlay to begin | |
267 | * at live_tree_max_phandle() + 1. Update references to the phandles to | |
268 | * the adjusted phandle values. | |
269 | * | |
270 | * The name of each property in the "__fixups__" node in the overlay matches | |
271 | * the name of a symbol (a label) in the live tree. The values of each | |
272 | * property in the "__fixups__" node is a list of the property values in the | |
273 | * overlay that need to be updated to contain the phandle reference | |
274 | * corresponding to that symbol in the live tree. Update the references in | |
275 | * the overlay with the phandle values in the live tree. | |
276 | * | |
277 | * @overlay must be detached. | |
7941b27b | 278 | * |
269f1a67 FR |
279 | * Resolving and applying @overlay to the live expanded devicetree must be |
280 | * protected by a mechanism to ensure that multiple overlays are processed | |
281 | * in a single threaded manner so that multiple overlays will not relocate | |
282 | * phandles to overlapping ranges. The mechanism to enforce this is not | |
283 | * yet implemented. | |
7941b27b | 284 | * |
269f1a67 | 285 | * Return: %0 on success or a negative error value on error. |
7941b27b | 286 | */ |
25e16877 | 287 | int of_resolve_phandles(struct device_node *overlay) |
7941b27b | 288 | { |
25e16877 | 289 | struct device_node *child, *local_fixups, *refnode; |
5581a95f | 290 | struct device_node *tree_symbols, *overlay_fixups; |
25e16877 | 291 | struct property *prop; |
7941b27b PA |
292 | const char *refpath; |
293 | phandle phandle, phandle_delta; | |
294 | int err; | |
295 | ||
d9181b20 FR |
296 | tree_symbols = NULL; |
297 | ||
624ab2a4 FR |
298 | if (!overlay) { |
299 | pr_err("null overlay\n"); | |
d9181b20 | 300 | err = -EINVAL; |
32bed310 | 301 | goto out; |
624ab2a4 FR |
302 | } |
303 | if (!of_node_check_flag(overlay, OF_DETACHED)) { | |
304 | pr_err("overlay not detached\n"); | |
d9181b20 | 305 | err = -EINVAL; |
32bed310 | 306 | goto out; |
624ab2a4 | 307 | } |
7941b27b | 308 | |
f94823f2 | 309 | phandle_delta = live_tree_max_phandle() + 1; |
25e16877 | 310 | adjust_overlay_phandles(overlay, phandle_delta); |
da56d04c | 311 | |
25e16877 FR |
312 | for_each_child_of_node(overlay, local_fixups) |
313 | if (!of_node_cmp(local_fixups->name, "__local_fixups__")) | |
da56d04c PA |
314 | break; |
315 | ||
624ab2a4 FR |
316 | err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta); |
317 | if (err) | |
32bed310 | 318 | goto out; |
da56d04c | 319 | |
25e16877 | 320 | overlay_fixups = NULL; |
7941b27b | 321 | |
25e16877 | 322 | for_each_child_of_node(overlay, child) { |
624ab2a4 | 323 | if (!of_node_cmp(child->name, "__fixups__")) |
25e16877 | 324 | overlay_fixups = child; |
7941b27b PA |
325 | } |
326 | ||
25e16877 | 327 | if (!overlay_fixups) { |
a67976ec | 328 | err = 0; |
7941b27b PA |
329 | goto out; |
330 | } | |
331 | ||
4458db4c | 332 | tree_symbols = of_find_node_by_path("/__symbols__"); |
25e16877 | 333 | if (!tree_symbols) { |
624ab2a4 | 334 | pr_err("no symbols in root of device tree.\n"); |
7941b27b | 335 | err = -EINVAL; |
32bed310 | 336 | goto out; |
7941b27b PA |
337 | } |
338 | ||
25e16877 | 339 | for_each_property_of_node(overlay_fixups, prop) { |
7941b27b PA |
340 | |
341 | /* skip properties added automatically */ | |
25e16877 | 342 | if (!of_prop_cmp(prop->name, "name")) |
7941b27b PA |
343 | continue; |
344 | ||
25e16877 FR |
345 | err = of_property_read_string(tree_symbols, |
346 | prop->name, &refpath); | |
9f27ede4 | 347 | if (err) |
32bed310 | 348 | goto out; |
7941b27b PA |
349 | |
350 | refnode = of_find_node_by_path(refpath); | |
351 | if (!refnode) { | |
7941b27b | 352 | err = -ENOENT; |
32bed310 | 353 | goto out; |
7941b27b PA |
354 | } |
355 | ||
356 | phandle = refnode->phandle; | |
357 | of_node_put(refnode); | |
358 | ||
25e16877 | 359 | err = update_usages_of_a_phandle_reference(overlay, prop, phandle); |
7941b27b PA |
360 | if (err) |
361 | break; | |
362 | } | |
363 | ||
364 | out: | |
32bed310 MF |
365 | if (err) |
366 | pr_err("overlay phandle fixup failed: %d\n", err); | |
25e16877 | 367 | of_node_put(tree_symbols); |
7941b27b PA |
368 | |
369 | return err; | |
370 | } | |
371 | EXPORT_SYMBOL_GPL(of_resolve_phandles); |